Conventional microfabricated electrode arrays by themselves are often not mechanically robust enough to be inserted into tissue. Therefore, they must be coupled to a guide tube that is strong enough to maintain a straight trajectory and resist buckling while being inserted into tissue. The electrode arrays are generally coupled to electrical subsystems that are larger than the diameter of the guide tube. Thus, in order to remove a conventional guide tube while maintaining the position of the implanted electrode array, the electrical subsystem must be decoupled from the electrode array and the guide tube is slid off. Decoupling and recoupling the electrical subsystem can be challenging, and any recoupling is potentially exposed to fluids and thus subject to electrical shorting, leading to failure. Thus, there is a need for an improved guide tube that is removable from the implantable device without decoupling the electrical subsystem from the microfabricated electrode arrays. This invention provides such an improved and useful guide tube.